Photo Gallery: Carboniferous Period

Carboniferous Swamp

Artwork by Dorling Kindersley/Getty Images

Characteristic of the Carboniferous period (from about 360 million to 300 million years ago) were its dense and swampy forests, which gave rise to large deposits of peat. Over the eons the peat transformed into rich coal stores in Western Europe and North America. The name "Carboniferous" refers to this coal.

Carboniferous Landscape

Artwork by Mary Evans Picture Library/Alamy

The Carboniferous period saw the appearance of the first extensive forests on Earth. The growth of these forests removed huge amounts of carbon dioxide from the atmosphere, leading to a surplus of oxygen. Atmospheric oxygen levels peaked around 35 percent, compared to 21 percent today.

Mount Rundle, Banff

Photograph by George F. Mobley

Mount Rundle in Banff, Alberta, Canada, at 9,838 feet (2,999 meters) is mostly made up of limestone from the Mississippian Age. In North America the Carboniferous period is divided into the Mississippian (Lower Carboniferous) and the Pennsylvanian (Upper Carboniferous). This system was adopted to distinguish the coal-bearing layers of the Pennsylvanian from the predominantly limestone Mississippian.

Carboniferous Ferns

Photograph by James P. Blair

Botanist Robin C. Moran studies Carboniferous ferns at the Missouri Botanical Garden in St. Louis, Missouri. Ferns made up a significant component of the terrestrial vegetation during the Carboniferous period. Fossilization of giant tree ferns is one of the sources for the huge coal deposits formed during the period.

Reef Tip Shark

Photograph by Nick Caloyianis

The oldest sharklike animals appeared during the Silurian period, but it's the Carboniferous that's called the "Golden Age of Sharks." During this time, the fish proliferated and evolved closer to today's modern sharks, such as the reef tip shark, pictured here.

Calamites Fossil

Photograph by James L. Amos

Calamites, a primitive seedless tree, grew in swamps about 300 million years ago, during the Carboniferous period. This fossil, which measures 6 inches (15 centimeters) tall, is in the collection of the Smithsonian Institution's National Museum of Natural History in Washington, D.C.

Horsetail Fossil

Photograph by John Cancalosi/Alamy

Perfectly preserved for more than 300 million years, a horsetail carries secrets from the Carboniferous period. Primitive vascular plants, horsetails (genus Equisetum) are often found in coal deposits.

Crinoid Fossil

Photograph by James L. Amos

The marine invertebrates called crinoids filled the seas during the Carboniferous period and even earlier. Their fossils are frequently found in limestone from the period, giving the Carboniferous the nickname the "Age of the Crinoids."

Cockroach

Photograph by Darlyne A. Murawski

One of the most dominant insects during the Carboniferous period, cockroaches don't look much different today—except for their size. Recent fossil finds have yielded roaches up to 3.5 inches (9 centimeters) long, about twice as big as today's pests.

Pacific Lamprey

Photograph by Darlyne A. Murawski

Lampreys, the oldest living lineage of vertebrates, have changed little since the Carboniferous period. There are currently about 35 species in existence; this one is the Pacific lamprey (Lampetra tridentatus).